One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,3)(5,6)(7,11)(8,12)(9,10)(13,14)(15,18)(16,24)(17,21)(19,22)(20,25)(23,26)(27,28)(2,3)(6,10)(11,12)(13,15)(14,18)(16,23)(17,22)(19,21)(20,25)(24,26)(27,28) involution — undirected(1,2,4,3)(5,7,9,8)(6,11,10,12)(13,16,18,25,19,26,17,27)(14,20,21,24,22,28,15,23)(1,3,4,2)(5,8,9,7)(6,12,10,11)(13,14)(15,17)(16,20)(18,21)(19,22)(23,27)(24,25)(26,28)(13,17,19,18)(14,21,22,15)(16,25,26,27)(20,23,28,24)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.